464 PETROLOGICAL ABSTRACTS AND REVIEWS 



Duparc, L., and Pamphil, G. " Sur l'issite, une nouvelle roche 

 filonienne dans la dunite," Comptes Rendus de VAcademie des 

 Sciences, CLI (19 10), 1136-38. 



The rocks described form dikes in massive dunites of the platinum 

 deposits in the basin of the river Iss. They consist mainly of horn- 

 blende, with subordinate pyroxene, labradorite in some cases, magnetite, 

 and apatite. Five, analyses are given. Si0 2 ranges approximately 

 from 33 to 47 per cent; Fe 2 3 from 3 to 9 per cent; FeO from 14 to 9 

 per cent; CaO from 16 to n per cent; MgO from 10 to 7 per cent; 

 total alkalies 2 to 3 per cent. In the quantitative classification, the 

 rocks fall in auvergnose and three unnamed subrangs. 



F. C. Calkins 



Duparc, L., and Wunder, M. " Sur les Serpentines du Krebet- 



Salatim (Oural du Nord)," Comptes Rendus de VAcademie 



des Sciences, CLII (191 1), 883-85. 



Describes dunites and harzburgites more or less completely altered 



to antigorite and bastite. Five analyses of these rocks and one of the 



inclosed calcareous hornfels are given. 



F. C. Calkins 



Grandjean, F. "Sur un mesure du laminage des sediments 

 (calcaires et schistes) par celui de leurs cristaux clastiques 

 de tourmaline," Comptes Rendus de VAcademie des Sciences, 

 CLI (1910), 907-9. 

 The author finds tourmaline an unfailing constituent of shales and 

 limestones. The crystals of this mineral in deformed rocks show a 

 middle portion normal in color and apparently undeformed, and ragged 

 terminal portions of paler hue. The terminal zones are considered due 

 to elongation of the tourmaline, and their average length (about 30 

 measurements is ordinarily sufficient) gives a co-efficient of deforma- 

 tion for the rock. 



F. C. Calkins 



Groth- Jackson. The Optical Properties of Crystals. New York: 

 John Wiley & Sons, 1910. Pp. xiv+309, figs. 121, colored 

 plates 2. 

 In spite of a number of good books on optical crystallography which 



have appeared within the past few years, no work has quite taken the 



